Permonosulfuric acid and sulphite treatment of wool and resulting product



2,739,034 Patented Mar. 26, 1956 PERMONOSULFURKC ACID AND SULPHITE TREATMENT OF W001. AND RESULTING PRODUCT Eric Tom Fell, Ambergate, England, assignor to Stevensons (Dyers) Limited, Ambergate, England, a British company No Drawing. Application April 17, 1952,

Serial No. 282,902

Claims priority, application Great Britain January 4, 1952 11 Claims. (Cl. 8-428) This invention relates to the treatment of wool for the purpose of reducing its tendency to felt or shrink when washed in aqueous liquors.

In patent application Serial No. 228,143, filed May 24, 1951, now Pat. No. 2,701,178, I have claimed a method of producing a shrink-resisting finish, which comprises treating the wool with a solution of permonosulphuric acid or salt thereof together with not less than 10% by weight of sulphuric acid.

I have now found that shrink resistance in wool may be produced by treatment with suitable solutions of permonosulphuric acid or its salts without the use of additions of such large quantities of sulphuric acid as employed previously, provided that, following treatment with these solutions, the wool is passed through solutions or dispersions of a certain type of reducing agent. 7

Accordingly, the present invention consists in a method of reducing the tendency of wool to felt or shrink, in which materials composed wholly or partly of wool are treated at any suitable stage of manufacture-with a solution of permonosulphuric acid or a salt or salts thereof,

with the effect of the permonosulphuric acid.

Treatment with the solutions of permonosulphuric acid or its salts may be made at temperatures ranging from cold to 70 C. and the bath of solutions or dispersions of salts of sulphurous acid may be at temperatures from 7 cold to boiling.

The solutions or dispersions of the salts of sulphurous acid are preferably at the pH given by the normal salts in solution or dispersion, but may also be used if alkaline or weakly acid.

I prefer to use normal sulphites rather than the acid salts. Where the treatment with permonosulphuric acid or its'salts has been carried out. on the acid side and it is desired to use an acid sulphite, it is better to rinse or neutralise the wool prior to treating with the acid sulphite.

Salts of sulphurous acid which have been found satisfactory include those of the following metals and radicles: sodium, lithium, potassium, aluminum, barium,

calcium, magnesium, manganese, strontium,- zinc and ammonia. Basic salts of sulphurous acid of the above metals have also been found successful.

The solutions may be applied to the woollen goods by immersion, padding or'spraying.

The duration of treatment varies with the concentration;

of chemicals used. Thus low concentrations of permonosulphuric acid or its salts in the first stage, or weak 'solutions or dispersions of salts of sulphurous acid in the second stage, require prolonged treatment, but by adjustment of the concentrations the time of treatment may be reduced to a few seconds only. The processis therefore applicable in either stage to 'continuous'-processing techniques as well as to the batch method, sinceby using solutions of suitable concentrations, the time of treatment can be adjusted to correspond to'the convenient time of passage of the goods through the baths.

The solutions are stable and do not losestrength rapidly during use. The permonosulphuric acid solution is more stable when it is free from foreign electrolytes and other impurities.

The following range of tests serves to illustrate the unique eifect obtained in the production of shrink resisting finishes by the use of permonosulphuric acid followe by subsequent sulphite treatment:

Pieces (1 part) of an all wool serge were treated at C. for 50 minutes in parts of 0.012 normal s olu tions of each of (a) hydrogen peroxide (b) persulphuric acid (0) permonosulphuric acid, all these solutions being brought to pH 2.2. 1

The pieces were then rinsed with water and half 0 each piece individually treated at 25 C. for 30 minutes in a bath containing 5 grams per litre of zinc sulphite;

The samples were rinsed and then submitted to shrinkage testing in the standard milling stocks with theresults given below. 4

Area shrinkage, percent Untreated 23.1 Hydrogen peroxide at pH 2.2 28.4 Hydrogen peroxide at pH 2.2 followed by zinc sulphite 21.6 Persulphuric acid at pH 2.2 26.8 Pei-sulphuric acid at pH 2.2 followed by zinc sulphite 21.8 Permonosulphuric acid at pH 2.2 21.1

Permonosulphuric acid at pH 2.2 followed by zinc sulphite 3.8 Zinc sulphite alone 22.0

The following are examples of the manner of carrying out the invention. Allparts are by weight.

Example 1 parts of previously scoured, damp wool are passed for a total time of 1 /2 seconds through a solution containing 36 parts of permonosulphuric acid in 1,000 parts of water at a temperature of 25 C., the pH of the solution being 0.5, adjusted with sulphuric acid.

The fabric is then squeezed through a mangle, run through the air for 10 seconds and immersed for 30 seconds in a solution of 100 parts of sodium sulphite crystals in 1,000 parts of water at 25 C. It is then rinsed with water and sent forward for normal finishing processes.

Example 2 A treating bath is made from 8 parts permonosulphuric acid, 1 part sulphated fatty alcohol 200 parts water.

Sulphuric acid is added so that the pH is 0.3 and the temperature adjusted to 35 C.

Scoured all wool knitted underwear fabric in the dry state is passed through a pad mangle with the bottom roller dipping in the treating bath described above. The mangle is so arranged as to give a retention of the treating liquor.

The wool is then run through the air for 10 seconds and immersed for 6 seconds in a solution of parts of sodium sulphite crystals in 1,000 parts of water at 35 C. The wool is then well rinsed.

1.9 Example 3 A bath is prepared containing 1 part of permonosulphuric acid in1,150 parts of water and is adjusted by means of caustic soda to pH 4.5.

38 parts of wool fabric are treated in this bathat 25 C. for 1 hour, after which a solution, suitably diluted and containing parts of sodium sulphite and 2 parts of sodium carbonate is added to the treating bath, the temperature being maintained at 25 C. Treatment is continued'for 30 minutes; the wool is then rinsed with water, and sent forward for normal finishing processes.

Example 4 38 parts of wool serge are treated at 30 C. for 1 hour in 1,150 parts of water containing 1 part of permonosulphuric acid adjusted to pH 1.4 by means of sulphuric acid.

The serge is then neutralized by a bath containing 2 parts of sodium carbonate in 1,000 parts of Water at 20 C. The time taken may be 5 minutes and after this the excess alkali is rinsed away with water. The wool is then treated at 25 C. for 30 minutes in a bath containing 20 parts of potassium bisulphite in 1,000 parts of Water g iV ing pI-I 4.7 initially and finally rinsed with plain water.

Example 5 A'dry all Wool fabric is passed through the "nip of a pad mangle, the bottom roller of which is dipping in a bathcontaining 5 parts of permonosulphuric acid and 1 part 'of 'sulphated fatty alcohol in 100 parts of water at 30 C. at pH 0.4. The solution licked up by the bottom roller immediately wets out the fabric in passage through the nip.

The fabric is then run through the air for 20'seconds and then 'passed through another pad mangle with the bottom roller dipping in the second treating bath containing parts of sodium sulphite crystals and 10 .parts of soda ash dissolved in 100 parts of water at a temperature of 30 C. The liquor taken up by the roller im- 'mediately frees the fabric from acidity during the squeezing action of the mangle.

The Wool fabric is then run through the air for 10 seconds and finally rinsed.

Example 7 50 parts of wool fabric already scoured by means of 's'ulphated fatty alcohol are treated at 25 C. for 40 minutes in a solution of 1 part of permonosulphuric acid in .parts of water at pH 1.7.

' The woollen material is then rinsed and passed for -10 seconds through a bath at 95 C. containing 10 parts of sodium sulphite crystals in 100 parts of water. is then rinsed and dried.

Example 8 80-parts of half hose made from 50% wool and 50% cotton are treated at 25 C. for 40 minutes in a bath containing l'part of permonosulphuric acid in 2000'parts of "water at pH 2.0.

The goods are rinsed twice and then treated for 30 minutes in a second bath at 25 C. containing 10 parts sodium'sulphite crystals, 3 parts of zinc sulphate and 1 part of commercial ammonia (S. G. O. 900) in 2000 parts-of water.

The fabric The half hose are then well rinsed and finished in the usual manner.

. Example 9 40 parts of wool cloth are treated at 60 C. for '15 minutes at pH 1.8 in a solution of 1 part of permonosulphuric acid in 1200 parts of water.

The cloth is then given one rinse at 60 C. and treated for .10 minutes in a bath at 40 C. containing 6 parts of magnesium sulphite in 1200 parts of water at pH 8.5. The cloth is then rinsed.

Example 10 40 parts of scoured Botany yarn are treated for 20 minutes at 26 C. in a bath containing 1 part of permono- Example 11 35 parts of scoured botany yarn are treated at 32 C.

for minutes in a solution of 1 part of permonosulphuric acid in- 1400 parts of water at pH 2.0.

The yarn is then rinsed, and treated for 30 minutes at -28" C. in a bath containing basic aluminum sulphite made from 7 /2 parts of sodium sulphite crystals, 1 /2 parts of ammonia S. G. O. 900 and 3 parts of potash alum in 1500 parts of water. The yarn is then rinsed.

Example 12 40 parts'of all wool fabric are treated at 25 C. for minutes in a solution of 1 part of permonosulphuric acid in 1200 part-s'of water, adusted to pH' 6.8 by means of caustic soda;

Thefabricis then rinsed and treated at 25 C. for 30 minutes in a second bath containing 5 parts of sodium sulphiterc'rystals and 2 parts of soda ash dissolved in 1000 .parts of water.

' Example 13 paits of'zinc'sulphite'inl000 parts ofwater at 27 C. and

tr'e'at'ed unde'rthese-conditions for 30 minutes. The wool is '{then 'rinse'd with water.

What I-claim is:

1. A method of treating textile materials consisting at "least in part of wool to reduce the tendency to shrink 'wirewwashed in aqueous liquors, comprising treating such materials'witha solution of a substance selected from the group c'onsisting of permonosulphuric acid and salts thereof, at a pH less than 8, followed by treating with a liquor containing a substance selected from the group consisting of normal, acid and basic salts of sulphurous acid and-compounds which produce such salts in solution.

2. A method of treating textile materials consistinga't 'l'e'astin part of wool to reduce the tendency to shrink when washed in aqueous liquors, as claimed in claim 1, wherein the temperature of the permonosulphuric acid bath i's within'the rangefro'm cold to C.

3. -A method of treating textile materials composed at least in part 'of wool to reduce the tendency to shrink when'washed in aqueous liquors, as claimed in claim 1 wherein the temperature of the second bath containing 7 bath.

The yarn is 5. A method according to claim 1, in which the woolen materials are treated in a continuous form for 1 to 30 seconds in a concentrated first bath followed by a treatment for 10 to 30 minutes in a dilute sulphite bath.

6. A method according to claim 1 in which the woolen materials are treated for 15 minutes to 1 hour in a dilute first bath followed by a treatment in a concentrated sulphite bath.

7. A method according to claim 1 in which the material istreated for 15 minutes to 1 hour in a dilute first bath, followed by a treatment for 15 minutes to 1 hour in a dilute sulphite bath.

8. A method as claimed in claim 1, in which the solutions are applied by one of the steps consisting of padding, brushing and spraying.

9. Woolen material and materials consisting at least partly of wool, which have been rendered resistant to shrinkage when washed in aqueous liquors, by treatment in a solution of a substance selected from the group consisting of permonosulphuric acid and salts thereof at a pH below 8 pH, the order of the time of treatment and concentration of solution being at least about one second at a concentration of at least about .05 followed by treatment with a liquor containing a substance selected from the group consisting of salts of sulphurous acid and compounds which produce such salts in solution.

10. A process which comprises treating a textile material consisting at least in part of wool with an aqueous solution of permonosulphuric acid having a pH below 2 at a temperature of about 25-35 C. and then subjecting the so-treated textile to an aqueous solution of a sulphite salt at about the same temperature, thereby to reduce the tendency of said textile to shrink.

11.- A process which comprises treating a textile material consisting at least in part of wool with an aqueous solution of permonosulphuric acid having a pH below 8, containing at least about .05% of permonosulphuric acid for at least about one second and then subjecting the sci-treated textile to an aqueous solution of a sulphite salt to reduce the tendency of such textile to shrink.

References Cited in the file of this patent UNITED STATES PATENTS 2,701,178 Fell Feb. 1, 1955 FOREIGN PATENTS 3,669 Great Britain 1875 451,026 Great Britain July 27, 1936 451,115 Great Britain July 29, 1936 561,521 Great Britain Oct. 15, 1932 579,584 Great Britain of 1945 614,966 Great Britain Dec. 30, 1948 784,828 France July 25, 1935 798,566 France May 20, 1936 

1. A METHOD OF TREATING TEXTILE MATERIALS CONSISTING AT LEAST IN PART OF WOOL OF REDUCE THE TENDENCY TO SHRINK WHEN WASHED IN AQUEOUS LIQUORS, COMPRISING TREATING SUCH MATERIALS WITH A SOLUTION OF A SUBSTANCE SELECTED FROM THE GROUP CONSISTING OF PERMONOSULPHURIC ACID AND SALTS THEREOF, AT A PH LESS THAN 8, FOLLOWED BY TREATING WITH A LIQUOR CONTAINING A SUBSTANCE SELECTED FROM THE GROUP CONSISTING OF NORMAL, ACID AND BASIC SALTS OF SULPHUROUS ACID AND COMPOUNDS WHICH PRODUCE SUCH SALTS IN SOLUTION. 